We can use aluminium in place of zinc for cathodic protection of rusting. Comment.
In cathodic protection the metal (here iron) to be protected from corrosion is connected by a wire to a more anodic matal ( like Al, Zn etc), so that all the corrosion occurs at this more active metal. Thus the parent metal is protected while the more active metal gets corroded slowly.
As the standard electrode potential of aluminium is more than that of zinc so Al is more anodic than Zn.
Thus we can better use aluminium in place of zinc for cathodic protection of rusting of iron.
At anode : Al → Al3+ + 3e–
At cathode : O2 + 2H2O + 4e– --->4OH–
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